Conventionally, a mobile terminal such as a mobile phone is equipped with an input apparatus having a touch sensor such as a touch panel and a touch switch serving as an element for detecting a user operation. Other than in the mobile terminal, the input apparatus having the touch sensor are widely employed in information appliances such as a calculator and a ticket vending machine as well as in home appliances such as a microwave, a TV, and lightning equipment, industrial equipment (FA equipment), and the like.
There are known a variety of types for the touch sensor to detect a contact such as a resistive film type, a capacitive type, an optical type, and the like. However, a touch sensor employing any one of these types detects an operation performed by a finger or a stylus pen but, when being contacted, does not physically deforms like a press-button switch.
Therefore, even when the operation to the touch sensor is correctly recognized by the input apparatus, the user having performed the operation cannot obtain feedback of the operation. Therefore, the user cannot obtain an operation sensation that may be obtained when the user presses a key or a button constituted by using a mechanical press-button switch. As such, there has been conventionally known a feedback method to provide vibration to the user's finger by vibrating the touch sensor when the touch sensor detects a contact (for example, see PLT 1 and PLT 2).